FIG. 4 is a schematic diagram of prior art printer device 200. Device 200 includes photoreceptor belt PBR, fuser section 202, transfer device 204, and prefuser transports PT arranged to move sheets of material S in process direction P from transfer device 204 to fuser section 202. Section 202 includes fuser rollers 206 and 208 arranged to displace sheets in direction P.
FIG. 5 is a graph showing torque load TL on a motor driving fuser rollers 206 and 208. FIG. 5 shows load TL as a sheet enters and exits rollers 206 and 208. Torque spike TL-1 occurs when the sheet engages rollers 206 and 208. Torque spike TL-2 occurs when the sheet disengages from rollers 206 and 208. As a thickness of sheet S increases, respective amplitudes of spikes TL-1 and TL-2 increase. If the thickness is large enough, respective jolts are caused by engagement of the sheet with rollers 206 and 208 disengagement of the sheet from rollers 206 and 208. These jolts cause undesirable disturbance in a photoreceptor section (not shown) with subsequent image artifacts.
FIG. 6 is a graph showing fuser drive velocity DV for fuser section 202. DV is substantially a mirror of TL. Spike DV-1 occurs with spike TL-1 and spike DV-2 occurs with spike TL-2. As a thickness of sheet S increases, respective amplitudes of spikes DV-1 and DV-2 increase. Further, increasing the thickness of sheet S delays the time at which a trailing edge of the sheet disengages from the fuser rollers.
Another problem associated with device 200 is increasing length L of sheet S to be greater than distance D between transfer device 204 and rollers 206 and 208, that is, sheet S is simultaneously engaged by roller the transfer device and rollers 206 and 208. Such simultaneous engagement causes undesirable image artifacts. Further, to prevent crumpling or distorting sheet S, the transfer device and fuser rollers 206 and 208 must displace sheet S at the same rate. In addition, an inter-document zone IDZ is typically maintained between sheets to facilitate test patterns and other quality control operations in photoreceptor section 202.